Method of forming friction protrusions on elastic, open-mesh garment fabric

ABSTRACT

A method of applying a resinous material to an elastic, openmesh fabric in spaced globs or in a narrow band and subsequently passing the fabric to an area maintained at an elevated temperature so as to set the resinous material and thus form friction protrusions on the open-mesh fabric.

United States Patent Bjorn-Larsen 1 Mar. 7, 1972 [54] METHOD OF FORMING FRICTION 2,291,545 7/1942 Ganz et al ..16l/73 PROTRUSIONS 0 L STIC, ()PEN. 2,893,315 7/1959 Reynolds et al... .117/38 X 3,350,215 10/1967 Jenhard et al. ..117/37 MESH GARMENT FABRIC Knut L. Bjorn-Larsen, 128 South Hacienda Ave., Glendora, Calif. 91740 Filed: Aug. 10, 1970 Appl. No.: 62,604

Related U.S. Application Data Continuation of Ser. No. 830,193, May 19, 1969, abandoned, which is a continuation of Ser. No. 494,822, Oct. 11, 1965, abandoned.

Inventor:

References Cited UNITED STATES PATENTS 2,196,492 4/1940 Clark et al. ..161/77 X FOREIGN PATENTS OR APPLICATIONS 1,150,647 6/1963 Germany ..1 18/502 1 ,002,497 2/1957 Germany OTHER PUBLICATIONS .German Printed Application B28739lVc/48c, Neuwirth et a1.,

Primary Examiner-Robert F. Burnett Assistant Examiner-Roger L. May Attorney-Harris, Kiech, Russell & Kern [57] ABSTRACT A method of applying a resinous material to an elastic, openmesh fabric in spaced globs or in a narrow band and subsequently passing the fabric to an area maintained at an elevated temperature so as to set the resinous material and thus form friction protrusions on the open-mesh fabric.

15 Claims, 5 Drawing Figures PATENTEDMAR 7 m2 3,647, 505

INVENTOR K/vur L. BJORN LAP-SEN BY A 7'T01Q/VEY5 f/Aee/s, MECH, RUSSELL. & Keg

METHOD OF FORMING FRICTION PROTRUSIONS ON ELASTIC, OPEN-MESH GARMENT FABRIC This application is a continuation of Ser. No. 830,193, now abandoned, which is a continuation of Ser. No. 494,822, also now abandoned.

This invention relates to garment manufacture and more particularly to an improved product and a method of forming friction protrusions on an elastic, open-mesh garment material such as the knit stretch fabric known as Spandex.

In a copending application, now US. Pat. No. 3,253,559, there is disclosed a stocking-supporting device incorporated in a girdle made up of a first band of the open-mesh, elastic material (Spandex or the like) adapted to fit about the upper limb of the wearer and a second band of the elastic material overlying the first band with plurality of friction members or protrusions on the surfaces of the respective bands; The bands are affixed to each other but are separable so as to receive a stocking top therebetween. The second band overlaps the first band and the friction members or protrusions serve to secure the stocking top in place between the overlapping bands. A mechanical friction lock is thereby established and retains the stocking top between the first and second bands. The friction protrusions of the garment material disclosed in the foregoing patent application is formed on the surface of the elastic garment fabric. This manner of surface bonding the protrusions to a single side of the elastic material has not proven wholly satisfactory.

It is a principal object of the invention to provide an improved method of forming friction protrusions on an elastic, open-mesh knit stretch fabric.

It is a still further object of the invention to provide an improved Spandex-type garment material having friction protrusions more securely bonded thereto.

It is a still further object of the invention to provide an elastic, open-mesh garment material characterized by friction protrusions formed of a synthetic resinous material possessing superior retention properties.

In the method of the invention Spandex or other elastic, open-mesh knit stretch garment material has applied to it a resinous material, generally in spaced globs or in a narrow band, and the garment material thereafter is passed to an area maintained at an elevated temperature where the resinous material is set up to form the friction protrusions of the garment. The viscosity of the resinous material is selected to permit penetration of the holes of the elastic garment material and the formation of a cohesive, integral resinous mass on the opposite sides thereof. Typically, the knit stretch material will have a mesh (openings per inch) within the range of 30 to 50 lengthwise of the material, and a widthwise mesh range of 25 to 45. A particularly desirable elastic knit stretch garment material typically has 43 openings per inch length of fabric and 32 openings per inch in the width direction. The Spandextype fabrics are stretchable in diametrically opposed directions. A popular elastic garment material of this type is made of blocked, segmented polyurethane copolymers synthesized from diisocyanates and glycols. The polyurethane resin is made up of high melting crystalline polymers intermixed with low-melting amorphous segments. It has been found that the resinous material used for the formation of the friction protrusions should have at time of application a viscosity in the range of 700 to 20,000 centipoises, Brookfield RVF viscosities determined at 77 F. with a number 4 spindle at 20 rpm. Throughout this specification and attached claims the viscosity is expressed in the foregoing Brookfield units.

It is important in the formation of the friction protrusions that there be a mechanical bonding or locking of the resinous material to the elastic garment fabric and to this end there must be a penetration of the holes of the garment fabric during application of the resinous material in order to form a cohesive, integral resinous mass on opposite sides thereof.

The resinous material used for formation of the friction protrusions is desirably a latex material, synthetic or natural rubber, or a vinyl plastisol, the latter being the preferred material.

Plastisols are physical mixtures of various vinyl resins, either homopolymers or copolymers and compatible plasticizers. The plastisols contain stabilizers and may contain pigmentation. The more popular plasticizers include dioctyl phthalate, diisooctyl phthalate, didecyl phthalate, dimonyl phthalate, dioctyl adipate, tricresyl phosphate and dioctyl sebecate. Frequently, a secondary plasticizer such as hydrogenated terphenyl, a chloroparaffin or a paraffinic hydrocarbon will be incorporated in the plastisol. A suitable composition for the plastisol for use in the invention is:

Parts by Weight Polyvinyl chloride resin Stabilizer 3 Titanium dioxide 5 Dioctyl phthalate 75 The homopolymer of vinyl chloride and various ones of the commercially available copolymers of vinyl chloride, for example, the copolymer of vinyl chloride and vinyl acetate may be used in the plastisol mixture.

Fusion of the plastisol at elevated temperatures drives the plasticizer into the resin and changes the plastisol into a homogeneous plastic mass possessing the excellent physical properties commonly associated with the vinyls. To obtain the maximum physical properties, the plastisols are generally heated at a temperature in excess of 200 F. and usually within a range of 240 to 375 F. and preferably at a temperature in the more limited range of 240 to 260 F. The actual time of heating required varies widely and will depend, among other considerations, on the plasticizer used, the amount of plastisol applied and the temperature selected. It is important that the conditions be selected to permit the plastisol to reach its fusion temperature. Typically, the elastic garment material with the applied plastisol thereon is exposed to the fusion temperature for at least 2 /2 minutes and generally for a period of time within the range of 2 to 7 minutes.

Various latexes may be employed in the formation of the protrusions of the plastic fabric. in addition to natural rubber latex, various ones of the aqueous synthetic resin latexes may be used such as the copolymer of butadiene and styrene, polybutadiene, polyisoprene, acrylonitrile rubbers and the like. A particular desirable latex for use in the process is the type generally known as GR-S-ZOOO, which contains a butadiene/styrene monomer charge content of 50-50 with a potassium soap of crude rosin as the emulsifier. A typical GR-S-2000 latex normally has a solid content within the range of 35 to 50 percent. An increase in the water content of the latex or lowering of the styrene content in the instance of the butadiene/styrene copolymer, lengthens the time needed for the synthetic resin latex to set. Thus, it is seen the length of time required in the heating step following application of the resinous latex to the fabric material depends largely upon the initial water content thereof. The latexes are usually dried and cured by exposure to a temperature in excess of 200 F., generally in excess of 220 F. and within the range of 22030 0 F. to evaporate the water and cure the rubber. It will be appreciated that somewhat higher temperatures may be employed. The time required in the curing or heating zone to set the rubber friction protrusions on a garment fabric may vary widely depending, among other considerations, on the particular latex employed, the water content of the latex and the temperature employed. Broadly speaking, the time within the curing zone to heat set the latex will usually be in excess of 5 minutes and generally within the range of 12 to 20 minutes.

Other advantages and objects of the invention will become apparent to those skilled in the art upon reference to the accompanying specification and drawings which disclose a presently preferred form of the equipment for the performance of the process and the production of the improved fabric.

Vinyl plastisol is the preferred material for formation of the friction protrusions and has been found to exhibit a polar affinity for the polyurethane knit stretch fabric. However, the

Hun-v.

principal mechanism for holding the protrusion to the knit stretch fabric is the mechanical bonding achieved through the penetration of the holes of the garment material to form the cohesive, integral mass on opposite sides thereof. Protrusions formed of a vinyl plastic possess exceptional gripping characteristics and in this respect are superior to rubber protrusions formed from a latex. It has been found in the formation of the protrusion mass that the knit stretch fabric should be held out of contact with any surface in order to avoid a too rapid penetration ofthe resinous material therethrough.

In the drawings,

FIG. 1 is a plan view, partially cut away, of equipment that may be utilized in the practice of the process of the invention;

FIG. 2 is a side elevational view, partially cut away, of the equipment of FIG. 1;

FIG. 3 is an isometric, fragmentary view of a section of the conveyor belt of the equipment of FIGS. 1 and 2;

FIG. 4 is a fragmentary section of the elastic, knit stretch fabric product of the invention showing several friction protrusions thereon; and

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4 through one of the friction protrusions.

Referring to FIGS. 1 and 2, it will be seen that the equipment used in the process of the invention includes an endless, nonmetallic conveyor belt which at its opposite ends encircles drums 12 and 14 which are mounted respectively on shafts 16 and 18. The shafts 16 and 18 on their outer ends carry cog wheels 20 and 22 which engage an endless drive chain 24. The shaft 18 is also splined to a driven pulley 28 which is driven by a V-belt 30 and drive pulley 32 of a variable speed drive mechanism which is powered by an electric motor 36. The provision of the drive chain 24 assures that drum 12 i will have a positive drive as well as drum 14.

The conveyor belt 24 is provided with means for holding a strip of the plastic fabric being processed a short distance thereabove, this means being in the embodiment illustrated three longitudinally extending rows of spaced spikes which spikes are desirably of a general cone configuration.

The apparatus at its opposite ends is provided with rolls 44 and 46 of the elastic fabric being processed. The latter roll 46 is a takeup roll of the finished product.

In operation of the process of the invention, a length of the elastic fabric, such as Spandex, is continually drawn from roll 44 and positioned on the retaining spikes 40 of the moving conveyor belt 10 after passing beneath a positioning roller 44. The retaining spikes 40 being generally conical in shape limit the distance to which the elastic fabric may approach the conveyor and aid in forming a smooth surface on the elastic fabric and in holding the holes of the fabric open. It is important in the practice of the process that the fabric be spaced out of contact with the moving conveyor. Various means may be employed to achieve this. The elastic fabric after being positioned on the conveyor is passed beneath an applicator head 46 supported immediately above the conveyor belt and fabric. The applicatorhead is supplied via line 48 with a stream of the resinous material, either a vinyl plastisol or latex, which is applied to the fabric being processed. As illustrated in FIG. 4, the resinous material may be applied in spaced globs to the fabric. Alternatively, the resinous material may be supplied in a continuous head. The resinous material has a viscosity which permits it to penetrate the holes of the fabric to form a cohesive, integral resinous mass on the opposite sides thereof but still sufficient viscose to substantially prevent dripping from the undersurface of the fabric before heat ,treatment. This is an important feature of the process of the invention in order to achieve the mechanical bonding possible with the formation of the protrusions or globs 50 on the opposite side of the fabric strip.

From the applicator head 46 the conveyor belt moves the fabric strip into the curing tunnel 54 which is maintained at the desired elevated temperature by a plurality of infrared lamps 56. The curing tunnel 54 at its opposite ends is provided with an entry shelf 58 and an exit shelf 60.

I claim:

1. A method of forming friction protrusions on an elastic, open mesh garment material having closely spaced holes therethrough, said method comprising:

supporting the garment material so that both sides of the material are held substantially out of contact with any surface by garment support means;

passing the garment material so supported to a first station and there applying a resinuous material to a portion of said garment material with application means held out of contact with the surface of said garment material, said resinous material having a viscosity permitting penetration of the holes of the garment material and the formation of a cohesive, integral resinous mass on opposite sides thereof; and

passing the garment material so supported to a second station maintained at an elevated temperature and there setting up the resinous material to form the friction protrusions on said garment material.

2. A method in accordance with claim 1 wherein the resinous material at the time of application has a viscosity in the range of 700 to 20,000 centipoises.

3. A method in accordance with claim 1 wherein the resinous material is a vinyl resin plastisol comprising a physical mixture of a vinyl resin and a compatible plasticizer; and

the elevated temperature is adequate to drive the plasticizer into the vinyl resin and change the plastisol into a homogeneous plastic mass, said homogeneous plastic mass providing the friction protrusions on said garment material.

4. A method in accordance with claim 3 where the vinyl resin plastisol has a viscosity within the range of 700 to 20,000 centipoises; and

the elevated temperature maintained at the second station is within the range of 240L to 375L F.

5. A method in accordance with claim 1 where the resinous material is a vinyl resin plastisol comprising a physical mixture of a vinyl resin and a compatible plasticizer having a viscosity within the range of 3,000 to 10,000 centipoises; and

the elevated temperature maintained at the second station is within the range of 240L to 260L F. which drives the plasticizer into the vinyl resin to change the plastisol into a homogeneous plastic, said homogeneous plastic providing the friction protrusions on said garment material.

6. A method in accordance with claim 5 wherein the plastisol is applied to the open-mesh garment material in a plurality of continuous beads.

7. A method in accordance with claim 5 wherein the plastisol is applied to the open mesh garment material in a plurality of spaced globs.

8. A method in accordance with claim 1 wherein the resinous material is a latex material.

9. A method in accordance with claim 8 wherein the latex material has a viscosity within the range of 700 to 20,000 centipoises; and

the elevated temperature maintained in the second station is within the range of 200L to 300L F. which cures the latex material to form the friction protrusions on said garment material.

10. A method in accordance with claim 8 wherein the latex material has a viscosity within the range of 3,000 to 10,000 centipoises; and

the elevated temperature maintained in the second station is within the range of 200L to 275L F.

11. A method in accordance with claim 9 wherein the latex material is applied to the garment material in a plurality of continuous beads.

12. A method in accordance with claim 9 wherein the latex material is applied to the garment material in a plurality of spaced globs.

13. A method in accordance with claim 1 wherein the garment supporting means comprises a moving endless conveyor having a plurality of spaced, generally conically shaped retaining spikes on its outer surface, the garment fabric being spaced from the outer surface of the conveyor and being l0l026 nun removably impaled on the retaining spikes of the conveyor, said retaining spikes holding the garment fabric on the endless conveyor.

14. A method of forming friction protrusions on elastic, open-mesh garment fabric having closely spaced holes therethrough, said method comprising:

providing a moving endless conveyor having a plurality of spaced generally conically shaped retaining spikes on its outer surface;

positioning an elongated strip of the garment fabric on the conveyor with said garment fabric being spaced from the outer surface of the conveyor and being removably impaled on the retaining spikes of said conveyor, said retaining spikes holding said garment fabric on the endless conveyor with its holes open;

moving the conveyor and the garment fabric to a first station and there applying a resinous material to a portion of the fabric with application means held out of contact with the surface of said fabric, said resinous material having a viscosity permitting penetration of the holes of the garment fabric and the formation of a cohesive, integral resinous mass on opposite sides thereof;

passing the conveyor and impaled garment fabric to a aql 1 second station maintained at an elevated temperature and there setting up the resinous material to form friction protrusions on said garment fabric; and

removing the strip of garment fabric from the endless conveyor at a third station.

15. A method of forming friction protrusions on an elastic, open-mesh garment material having closely spaced holes therethrough, said method comprising:

supporting the garment material so that both sides of the material are held substantially out of contact with any surface by garment support means;

passing the garment material so supported to a first station and there applying a resinous material to a portion of said garment material, said resinous material having a viscosity permitting penetration of the holes of the garment material and the formation of a cohesive, integral resinous mass; and

passing the garment material so supported to a second station maintained at an elevated temperature and there setting up the resinous material to form the friction protrusions on said garment material.

lum-

232 3 UNITED STATES PATENT OFF'ICE CERTIFICATE OF CORRECTION Patent No. 3 47 505 Dated M g rch 7 1972 Inventor(s) Knut L. 3jorn-I .grsen It is certified that error appears in .the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I" Col. 4 Claim 4, Line 34, "2401. to 3751. F" shou1 .d read I --240 to 375F--.

Col. 4: Claim 5, Line 41, "240L to 2601. F" should read "240 to 260F--.

C01. 4: Claim 9,' Line 57, "20OL to 300L F" should read --200 to 3009F- C01. 4: Claim 10, Line 64, "'200L to 2751. F" should read --200 to 275F--.

Signed and sealed this 18th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETGHER,JR. ROBERT GO'ITSCHALK Attesting Officer Commissioner of Patents 

2. A method in accordance with claim 1 wherein the resinous material at the time of application has a viscosity in the range of 700 to 20,000 centipoises.
 3. A method in accordance with claim 1 wherein the resinous material is a vinyl resin plastisol comprising a physical mixture of a vinyl resin and a compatible plasticizer; and the elevated temperature is adequate to drive the plasticizer into the vinyl resin and change the plastisol into a homogeneous plastic mass, said homogeneous plastic mass providing the friction protrusions on said garment material.
 4. A method in accordance with claim 3 where the vinyl resin plastisol has a viscosity within the range of 700 to 20,000 centipoises; and the elevated temperature maintained at the second station is within the range of 240* to 375* F.
 5. A method in accordance with claim 1 where the resinous materIal is a vinyl resin plastisol comprising a physical mixture of a vinyl resin and a compatible plasticizer having a viscosity within the range of 3,000 to 10,000 centipoises; and the elevated temperature maintained at the second station is within the range of 240* to 260* F. which drives the plasticizer into the vinyl resin to change the plastisol into a homogeneous plastic, said homogeneous plastic providing the friction protrusions on said garment material.
 6. A method in accordance with claim 5 wherein the plastisol is applied to the open-mesh garment material in a plurality of continuous beads.
 7. A method in accordance with claim 5 wherein the plastisol is applied to the open mesh garment material in a plurality of spaced globs.
 8. A method in accordance with claim 1 wherein the resinous material is a latex material.
 9. A method in accordance with claim 8 wherein the latex material has a viscosity within the range of 700 to 20,000 centipoises; and the elevated temperature maintained in the second station is within the range of 200* to 300* F. which cures the latex material to form the friction protrusions on said garment material.
 10. A method in accordance with claim 8 wherein the latex material has a viscosity within the range of 3,000 to 10,000 centipoises; and the elevated temperature maintained in the second station is within the range of 200* to 275* F.
 11. A method in accordance with claim 9 wherein the latex material is applied to the garment material in a plurality of continuous beads.
 12. A method in accordance with claim 9 wherein the latex material is applied to the garment material in a plurality of spaced globs.
 13. A method in accordance with claim 1 wherein the garment supporting means comprises a moving endless conveyor having a plurality of spaced, generally conically shaped retaining spikes on its outer surface, the garment fabric being spaced from the outer surface of the conveyor and being removably impaled on the retaining spikes of the conveyor, said retaining spikes holding the garment fabric on the endless conveyor.
 14. A method of forming friction protrusions on elastic, open-mesh garment fabric having closely spaced holes therethrough, said method comprising: providing a moving endless conveyor having a plurality of spaced generally conically shaped retaining spikes on its outer surface; positioning an elongated strip of the garment fabric on the conveyor with said garment fabric being spaced from the outer surface of the conveyor and being removably impaled on the retaining spikes of said conveyor, said retaining spikes holding said garment fabric on the endless conveyor with its holes open; moving the conveyor and the garment fabric to a first station and there applying a resinous material to a portion of the fabric with application means held out of contact with the surface of said fabric, said resinous material having a viscosity permitting penetration of the holes of the garment fabric and the formation of a cohesive, integral resinous mass on opposite sides thereof; passing the conveyor and impaled garment fabric to a second station maintained at an elevated temperature and there setting up the resinous material to form friction protrusions on said garment fabric; and removing the strip of garment fabric from the endless conveyor at a third station.
 15. A method of forming friction protrusions on an elastic, open-mesh garment material having closely spaced holes therethrough, said method comprising: supporting the garment material so that both sides of the material are held substantially out of contact with any surface by garment support means; passing the garment material so supported to a first station and there applying a resinous material to a portion of said garment material, said resinous material having a viscosity permitting penetration of the holEs of the garment material and the formation of a cohesive, integral resinous mass; and passing the garment material so supported to a second station maintained at an elevated temperature and there setting up the resinous material to form the friction protrusions on said garment material. 